Grip-nut for sheet metal fastening screws



March l0, 1953 A. J. HIGGINS GRIP-NUT FOR SHEET METAL FASTENING SCREWS Filecx Nov. 8, 1949 Patented Mar. 10, 1953 GRIP-NUT FOR SHEET METAL FASTENING SCREWS `Anthony/J. Higgins, PasadenmCalf.

ApplicationNovember 8, 19149,` 'jSerialNm` `136,163

54 Claims. 1

The present invention relates to grip nuts `for screws used to hold two or more pieces off sheet metal in functional position, and linds its application in many industries using sheet metalfin the fabrication of numerous items of consumer goods and other goods, such as, stoves, refrigerators, furniture, automobiles, aircraft, `et cetera, in fact in any assembly joined by screws wherein it is difficult to manually `hold a nut in position for application upona screw; and,

In view thereof, it is a prime object of the invention to provide a new and improved 'grip `nut for use in conjunction with `sheet metal andother assemblies.

A further object of the invention is to provide a grip nut which offers a minimum resistance in application to work and a maximum resistance to reverse movement of a screw.

A still further object of the invention is the provision of a grip nut having the afore-mentioned characteristics, which is susceptible of repeated application without notable loss `of gripping efficiency.

A still further object of the 'invention is the provision of a grip nut having each of the aforementioned characteristics, and having means which are self-centering and self-retaining in and with respect to a screw hole inthe work. A still further object ofthe invention is toprovide a, grip nut having a spiral spring' xedly centered upon the screw opening of the nut, the convolutions of the spring being directed oppositely from the lead of the Vthread of theA screw whereby upon advancing the screw the convolutions of the spring tend to be iin-wound and whereby upon reverse rotation of the screw 'the convolutions of the spring grip `the screw under an increasing degree of tension.

A still further objectief the invention is to provide a grip nut having a spiral spring ai'lixed to the body thereof and having its convolutions centered upon a screw opening in the nut, the convolutions of the spring being so positioned and arranged as to be spreadable to receive an advancing screw and to be constricting upon the screw when reversely rotated whereby the screw is restrained from disengagement therewith.

Still another object of the invention is to provide a grip nut having a spiral spring secured upon one of the sides thereof for screw gripping purposes and having a tapered neck upon the other of the sides thereof for insertion in a drill hole in the work whereby upon insertion thereof in a preformed screw opening or hole in the work, the `nut is self-centered and supported in relationshipV thereto against gravitational `dislodge- Tment. i

vother objects `of the invention, fas well-as features and advantages thereof `may be noted from a study of the accompanying detailed description. the drawing, and the sub-joined claims.

In 'the drawing:

`Figure 1 is an `end view of the grip nutof this invention; and,

Figure 2 is an elevational view of the lbtclibf the nut showing `the pancake springY in functional position.

Figure 3 is a sectional view as seen alone line 3 3, in VFigure 2.

Figure 4 isa side view of the'nut'; and.

Figure 5 vis a front `elevational viewof the nut.

Figure 6 is a transverse sectional view 'as seen alnog line 6 6, Figure.

Figure 7 is a transverse sectional view through two sheets of metal lshowings screw with `a nut thereon in application to the work as represented by thesheets of metal; and,

Figure 8v is a view generally analogous to Fig` ure '1, except that here the grip nut is shown in section to better illustrate thefmanner in which the pancake spring `engages the advanced screw, counter-clockwise rotation of the screw would cause the spring to constrictingly engage` the screw under an increasing degree of tension.

Figure 9 is a sectional view `as seen along line 3'-3 in Figure 2 of the grip nut body before the springismounted.

Figure 10 is a side-elevational view ofthe pancake spring detached from the, body of the nut. the spring is here positioned to receive the advance of a screw being applied to the work and when so advanced tends to unwind or spread Athe convolution of the spring, reverse movement of a screw tightens the convolutions of the spring upon the screw.

Reference to the drawing will show thaty the grip nut I2 of this invention is formed with a fiat body portion It having up-turned sides I6 for strengthening against tension when vapplied `in functional use. The guage of the metal `com- I prising the body of thenut, as well as the dimensions thereof, including the depth of the.. up- .turned sides I5 is of course proportional to the required duty.

The center ofthe body I4 is `pierced to form a screw opening I8 and the material dis-placed in 'forming the opening` I8 is extruded to form a tubular neck 20 the sides of which are convergingly inclined toward the medial longitudinal center thereof as indicated at 2l in Figune 1. The dcgn'se` of the conversing anslllarity is generally indicated. at X Wittmut Ibeing spe- `c-iiic, however, the duree o!" sentences,-` of the with and is contiguous withfthe opening i8, land Y is adapted to `form a seat for a pancake spring l y 28 which is held therein by means of tabs 30 which are struck from the -bodyof the nut', so

that the central opening 32 of-the spring is as concentric as may be with the medial longitudinal center of the opening I8. Y The guage of the material comprising th spring should be such as to permit the inner turn of the spring to rest or be seated in a substantial manner within the groove formed by the threads of the screw, and the diameter of the innermost convolution of the spring should be suchv as to permit the entry of a plural number of threads upon the tip of the screw before. noticeable-expansion thereof takes place, thereby enabling Athe nib 34 and its associated spring 4 ment involved which is deformed by compression, ruptured or otherwise harmed by successive uses, nor is the nut deteriorated or otherwise harmed by heat, and Within the tolerance of the metals used in constructing the nut, it is not subject to corrosion.

Having thus described my new and improved grip nutv in its Jpresently preferred form, that which I desire to protect by Letters Patent, is as follows:

71. A sheet metal fastening device, said device y,comprising a body having a horizontal face portion formed with slits in the edge `of a pair of oppositely disposed edges thereof so as to define tabs therein and fbeing formed with a medially ,disposed aperture extending therethrough, a spring, said spring being of coiled pancake form Y having an inner convolution diameter smaller convolution to accommodate itself to the best seating position among the threads of the screw.

The lpancake spring may be formed with two or more convolutions, but I find that two to three complete turns are suicient to provide an amount of elasticity for expansion or unwinding to permit easy entry of a screw when applied to a nut, and toconstrictingly carry over and around the screw when reversely rotated whereby the screw is gripped in a progressively tighter band as the screw is counter-rotated, but regardless of the number of convolutions formed in the spring, I form the nib 34 upon the free end of the innermost spring convolution, and this nib serves las a pilot to facilitate engagement with the threads of the screw `when being appliedto the Work.

It is believed it will .be apparent from the preceding description that I have created a novel grip nut, a nut which is particularly adapted to use in sheet metal fabrications, and v the floor, benchor `jig, and it will remain so l positioned when handled with ordinary care, and

in addition to Ithis feature and of equal or greater importance is the action of the spring -23 in the assembly comprising the nut as an entity, *for it will be noted that the convolutions of the spring are formed in such manner as to expand when driving a screw, and hence yoffers but neg- Yligible resistance thereto, but upon counterrotation o-f the screw, the -convolutions of the 'spring will tighten ythemselves around the spring lin a constricting grip which builds to arnaximum pressure suiicient to hold the screw in functional "position againstu all but 'deliberate manual 1removal thereof; Itis 'also tobe noted that the l"grip nut herein'shown and' described `is capable 1 iof repeated use for there is no structuralr'elethan the diameter of said aperture and medially dis-posed around said aperture and being secured in functional use position upon the body of said device by inturning and `depressing said tabs upon oppositely located sides of the outer coil thereof.

2. A sheet metal screw fastening device, said device being formed of rectangular sheet metal stock having a central horizontal face formed with oppositely disposed tabs in the edges thereof and being apertured medially thereof, a depressed annular seat upon one face of said device concentric with said aperture, a pancake type coil spring adapted to have its outer convolution rest upon said annular seat, said aperture yhaving a greater diameter than the diameter of the inner convolution of said pancake spring, said pancake type spring being secured in said depressed seat by inturning and depressing said tabs on the outermost convolution thereof whereby the inner coil of the spring is free for extension outwardly of a plane coincidental with `the top surface of the outer convolution of said spring.

3. The combination with a sheet metal screw, of a nut therefor, said nut comprising a piece of rectangular sheet metal stock having a horizontal face portion apertured medially therethrough and having two unidirectional flanged sides, a tab struck from each of the remaining sides of said Vnut, a pancake type spring, a seat for said spring, said seat being depressed in said vnut and being' medially disposed around said aperture and being so formed that the depressed sides thereof form a shoulder adapted to hold said spring against drift, the diameter of said aperture being greaterfthan the diameter of the 'innermost convolution of said spring so as to facilitate adjustment of a sheet metal screw with respect to said spring, said spring being secured in said seat by inturning and depressing said tabs `upon the outer convolution of said spring so as'to enable the inner convolution thereof to be extended outwardly of the face portion of the nut 'upon insertion of a screw therethrough.

4. In combination with agscrew having a taperednib comprising theleading end thereof, a nut for said screw, said nut having a" body com'- ,prvising a'single'piece of flat sheet metal stock ,partiallyjslitted upon two sides so as to ,define 'a pair ofroppositely located tongues and being further formed with a non-threaded aperture extending therethrough, a pancake spring upon the outer face of the nut, the diameter of the aperture Ltlnough saidnut-andy the diameter of the inner .-mpst'conv-olutionsofn saidjspring being of unequal value wherein the diameter of saidaperg ture is the greater thereof, said spring being formed with a pilot nib on its inner coil and being centered with respect tothe medial transverse axis of said aperture and being secured in functional use position by in-turning said tongues upon the outer convolution thereof, said spring being so arranged as tdbecome of elon gato-conical form upon clock-wise rotation of said screw entering therein through said aperture and being adapted to constrictingly bind upon the screw upon counter-rotation thereof.

5. In a nut of the class wherein a body is formed of a thin at piece of sheet metal having an aperture formed medially therethrough and wherein securing tabs are formed uponY the ends of the body by slotting and infoldingglupon a face of said body the material denedbylsaid slots, the combination with said body ofa pancake type extensile spring comprising anu'mber of spiral convolutions of material wherein the outer most convolution is anchored upon said face of the body of the nut by said infoldedvtabs and wherein the inner most convolution `terminates in a. nib adapted to pilot said innermost spring convolution along the threads of a screw inserted through said aperture and rotated through the inner most convolution of the spring whereby lateral extension thereof from-said face on said body` longitudinally of the medial axis `of the springis had by screw thread pressure, said aperture and said inner most spring convolution being differentiated in diametrical value in favor of said aperture.

' ANTHONY J. HIGGINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 

